Target with scanning projectile sensors



Sept. 17, 1968 A. M. ROCKWOOD ET AL 3,401,937

TARGET WITH SCANNING PROJECTILE SENSORS Filed Feb. 15, 1965 4 Sheets-Sheet l hz/eniors 464922 7 jack FM JiWV-H.

Sept. 17, 1968 ROCKWQOD ET AL 3,401,937

TARGET WITH SCANNING PROJECTILE SENSORS 4 Sheets-Sheet 2 Filed Feb. 15, 1965 Sept. 17, 1968 ROCKWQOD ET AL 3,401,937

TARGET WITH SCANNING PROJECTILE SENSORS 4 Sheets-Sheet 5 Filed Feb. 15, 1965 Sept. 17, 1968 A. ROCKWOOD ET AL 3,401,937

TARGET WITH SCANNING PROJECTILE SENSORS 4 Sheets-Sheet 4 Filed Feb. 15, 1965 mmN United States Patent TARGET WITH SCANNING PROJECTILE SENSORS Albert M. Rockwood, North Muskegon, Jack A. Russell and Anthony J. Gretzky, Muskegon, and Bradford J.

Baldwin, Fruitport, Mich., assignors to Brunswick Corporation, a corporation of Delaware Filed Feb. 15, 1965, Ser. No. 432,787 18 Claims. (Cl. 273102.2)

ABSTRACT OF THE DISCLOSURE Sensing apparatus for targets adapted to be hit by missiles within a pre-determined pattern including first and second coordinates of a missile within the pattern, each system including means for sweeping a beam of light across the pattern, timing means for timing the sweep of the beam of light across the pattern, means responsive to the beginning of the sweep of the beam of light across the pattern to actuate the timing means, means responsive to the disruption of the light beam by a missile in the pattern to deactuate the timing means and means responsive to the termination of the sweep of the light beam across the pattern for resetting the timing means.

Disclosure An object of the invention, in general terms, is to provide a new and improved archery range.

Another object of the invention is to provide a novel archery game suitable for league play providing enjoyment for the archer and designed to maximize participation.

More specifically, it is an object of the invention to provide a novel archery game similar to ten pin bowling wherein ten frames with generally two shots per frame are provided, the shots being directed at a target having ten regions of varying degrees of difl'iculty to hit which are accorded values from one to ten, there being provision for the acquiring of strikes and spares and the accompanying bonus points by hitting certain of the regions or combinations thereof with certain arrows. In the first nine frames a maximum of two arrows per archer are fired, while the tenth frame permits a maximum of three shots. A hit on the target region valued at ten by the first arrow of a frame is considered a strike and terminates that frame for that archer. Such an occurrence is scored in each frame as ten plus the value of the target regions hit by the next two arrows unless the first of the subsequent two arrows does not hit the region valued at ten and the total value of the two subsequent arrows is greater than ten. In this case, the score for a strike is ten plus the value of the region hit by the first of the two subsequent arrows. The second of the two subsequent arrows does not score. A spare is scored as ten plus the value of the next subsequent arrow and is achieved by hitting the target regions whose combined total equals ten with the two arrows of any given frame. When the archer does not obtain a strike with the first arrow of a frame, and his second arrow hits a target region whose value when combined with the value of the region hit by the first arrow (1) exceeds ten, the score of the second arrow is not counted and the archer receives only the score of the first arrow, or (2) is less than ten, the archer receives the combined score of the two arrows. A strike or a spare in the tenth frame permits the firing of two and one bonus shots respectively, while a complete miss of the target in any frame is scored as zero.

Another object of the invention is the provision of an automatic archery range including a firing line or shooting station from which arrows are fired in a flight path towards a target, a self ejecting arrow receiving and holding 3,401,937 Patented Sept. 17, 1968 ice backstop behind the target, an arrow collector beneath the backstop, arrow return means for receiving arrows from the collector and returning them to a quiver adjacent the firing line or shooting station, a target monitor observable by an archer from the shooting station or firing line for indicating to the archer or to spectators where the arrows have hit the target and means for scanning the flight path for sensing the position on the target hit by fired arrows and operating the target monitor.

Another object of the invention is the provision of means for automatically determining the point of contact of the arrow with the target independently of mechanical or physical contact with the arrow including first and second systems for scanning the arrow flight path with a beam of light to respectively determine a first and a second coordinate of the arrow within the flight path. Each systerm includes means responsive to the initiation of the sweep of a beam of light across the flight path for actuating timing means which are deactivated upon the presence in the light beam of an arrow passing to the target. There is also provided means responsive to the termination of the sweep of the light beam across the flight path for resetting the timing means. The signal from the timing means is fed to a servo mechanism which converts that signal to an indication on a target monitor of the point of entry of the arrow into the target.

Other objects of the invention will become readily apparent from the following detailed description taken in connection with the drawings wherein:

FIG. 1 is a longitudinal section through a preferred form of the invention, approximately along the line 11 of FIG. 2;

FIG. 2 is a transverse section of FIG. 1 taken approximately along the line 22;

FIG. 3 is another transverse section of FIG. 1 taken approximately along the line 3-3;

FIG. 4 is a side view of a preferred form of the backstop and scanning mechanism of the invention;

FIG. 5 is a front view of a backstop and scanning mechanism, used in a form of the invention;

FIG. 6 is a schematic diagram of a form of the scanning circuitry used in the invention;

FIG. 7 is a plan view of the scoreboard and associated indicating mechanism;

FIG. 8 is a front elevation of the scoreboard and associated indicating mechanism;

FIG. 9 is a side view of a fragment of FIG. 8.

As shown schematically in FIG. 1, an archery range according to the invention includes a shooting station or firing line manned by archer 22 firing arrows 24 at a target 26 spaced therefrom. Behind the target 26 is a self-ejecting backstop mechanism generally designated as 28. Below the target 26 and the backstop mechanism 28, is a collector 29 formed of a plate sloping forwardly and to one side as seen in FIG. 2. An arrow return mechanism is in close proximity to the collector 29 and comprises a pair of narrowly spaced belts 30a, 30b which feed to a conveyor 32 which in turn leads to an upwardly inclined pair of narrowly spaced belts 34a, 34b. The inclined belts 34a, 34b empty into a quiver, generally designated 36, adjacent the archer 22. The specific construction of the arrow return mechanism will be described in greater detail below. A target monitor 38 is placed near the archer 22 for indicating arrow hits on the target 26.

The target 26 may comprise the usual penetrable target sheets, having the desired target markings thereon, placed on the forward grid of the backstop mechanism 28. Preferably, however, the target 26 is formed of a facing of a self-healing nature as is well known in the art. The invention contemplates the use of a projector 27 for projecting suitable target markings onto the screen facing. 'In this way the projector 27 may be programmed with a number of different target markings which may be remotely selected for projection on the target by the archer.

The self-ejecting backstop mechanism 28 of the invention is illustrated in greater detail in FIG. 4. It comprises a pair of spaced grids 50, backed by a movable plate 52 formed of any material sufliciently hard and thick to preclude penetration by the fired arrow and, yet able to absorb the kinetic energy of the arrow. On the upper and lower extremities of the plate 52 are mounted carriages 62 having 'wheels 64 on tracks 66. The carriages 62, wheels 64 and tracks 66 serve to movably mount the plate 52 for movement toward and away from the grids 50. The mechanism for moving the plate 52 toward and away from the grids 50 comprises a member 54 attached to the back of the plate 52 and having therein an elongated slot 56. An eccentric pin 58 is received in the slot 56 and is rotated by a conventional one revolution motor 60. Actuation of the one revolution motor 60 will result in the plate 52 reciprocating toward and away from the grids 50. The apertures in the grids preferably comprise a high percentage of the total area of the grids so as to minimize the possibility of a direct hit of the solid portions of the grid by an arrow causing the arrow to bounce straight back towards the archer.

The invention also contemplates that the distance between the plate 52 in its away position and the forwardmost grid 50 or the target 26 is less than the distance between the tip of an arrow and the beginning of the fletching. When such spacing is used the fletching of the arrow never comes in contact with portions of the grid 50, thus precluding damage to the fletching. Finally, the size of the apertures in the grids 50 are such as to loosely receive an arrow and to retain the arrow therein substantially only under the influence of gravity. Thus, a fired arrow, will lodge loosely in the apertures of the grids 50 after being brought to a halt by its contact with the plate 52. At some predetermined time the one revolution motor 60 is actuated causing the plate 52 to move toward the grids 50. This causes the arrows to be slidably ejected from the grids 50. It will be appreciated that through suitable means, such as a transducer and a stepping switch, the backstop can be programmed to eject arrows after any predetermined number have been halted thereby. As stated previously, the target face and the torwardmost grid 50 are intended to be substantially coextensive. Thus, it will be seen that the use of a backstop according to the invention results in the arrows partially protruding from the target where they may be observed by the archer until such time as plate 52 is actuated and the arrows are automatically ejected. Accordingly, this feature of the invention provides retention for observation purposes as Well as for automatic ejection.

Placed about the arrow flight path, as a safety feature, is a deflector 40. Depending on the shape of the target 26, the walls of the deflector 40 may take the shape of a truncated pyramid as shown in FIG. 1, or the 'frustum of a cone. Associated with the deflector walls 40 is a contact transducer 42 or a microphone of sutficient sensitivity to determine when the deflector walls 40 have been hit by an arrow 24. Through conventional wiring such as a relay, the signal induced can be made to preclude operation of the scanning circuit and to show up on the target monitor 38 as a miss, thus informing the archer 22 that his last shot has been misdirected. This feature is necessary as the deflector walls 40 are arranged to deflect the arrow into the backstop 28 past the scanning mechanism and such a shot would show up as a score unless the fact that it has previously hit the deflector 40 is somehow indicated to the archer 22.

To enable the archer 22 to be constantly aware of his score with each arrow shot, a target monitor 38 is arranged in close proximity to the archer as seen in FIG. 1. By means of a mechanism described below, the target monitor 38 indicates to the archer where his last arrow has hit the target. To feed appropriate signals to the target monitor 38 to indicate the location of the arrows corresponding to be hits on the target 26, the invention provides a scanning mechanism generally designated 25 located ahead of the target 26. As shown more clearly in FIGS. 4 and 5, this scanning mechanism comprises a pair of systems, each system being identical with the other, wherein one system determines one angular coordinate of the position of the arrow within a flight path and the other system determines another angular coordinate of the position of the arrow within the flight path. Since the two systems are identical, only one will be described in detail. It should be noted that as used herein, the term flight path refers to the general area, both in front of and behind the target 26, in which arrows are intended to be fired, as contrasted to the line of flight taken by any given arrow.

An arcuate mirror 86 (see FIGS. 4 and 5) is placed about the periphery of the flight path near the target 26. At the focal point of the mirror is placed a light source providing a rotating beam of light. This function is achieved by means of an electric motor 70 rotating a drum 74 having equally spaced apertures 78 in its periphery. Mounted within the drum 74 is a light source 82. A first photocell is disposed along an edge of the flight path so as to be energized by the rotating light beam as it begins its sweep across the flight path. A second photocell 94 is disposed at the focal point of the mirror adjacent the light source in such a position as to be energized by the light beam upon reflection of the beam by the mirror 86 at all times during the sweep of the light beam across the flight path. In order to accommodate the placing of both the light source and the second photocell at the point of the mirror, both are slightly inclined to the vertical but in opposite directions (see FIG. 4) such that a light beam reflected from the mirror will not retrace its path back to the source, but will diverge slightly therefrom and strike the second photocell. A third photocell 98 is disposed along another edge of the flight path in such a position as to be energized by the light beam upon completion of its sweep across the flight path. By this arrangement, it is apparent that the first photocell 90 will be energized only at the beginning of the sweep of the light beam across the flight path, and that the third photocell 98 will be energized only at the end of the sweep of the light beam across the flight path. By virtue of reflection of the light beam by the mirror 86, it is apparent that the second photocell 94 will be energized continuously throughout the sweep of the light beam across the flight path unless the beam is interrupted at some point in that sweep. This interruption occurs when an arrow 24 passes through the flight path. Of course, in order for this sensing means to be effective, the time required for a single sweep of the beam across the flight path must be less than the time taken by an arrow in passing wholly through a plane perpendicular to its line of flight. For example, if it is considered that the shortest arrow commonly used is of a length of 24", and the maximum velocity of the arrow upon reaching the target is 350 feet per second, then it is apparent that the time for the sweep must be no longer than of a second. Accordingly, a drum 74, having five equally spaced apertures 78 must be rotated at 2100 rpm, in order to achieve a sweep time for one beam of 5 of a second. Obviously, however, other combinations of arrow lengths, drum speeds and number of apertures in the drum can be used.

The signals from the various photocell are transformed into a reading on the target monitor 38 by the following means. With reference to FIG. 6, one embodiment of the invention for transforming the signals comprises a scanning circuit connected to a source of electrical power and having a constant current generator 100. The constant current generator 100 is connected to a first silicon control switch 102 (a silicon control rectifier used as a switch), which is controlled by the first photocell 90.

Connected in series with the silicon control switch 102 across the source of electrical power is a diode 104 and a condenser 106. Connected in parallel with diode 104 and the condenser 106, is a second silicon control switch 107 which is controlled by the second photocell 94, and a low impedance relay coil 110. Since silicon control rectifiers when used as switches begin to conduct only when stimulated by a positive pulse, and the second photocell 94 is arranged to be constantly energized except when an arrow is present as described above, it is necessary that the polarity of the connection of the second photocell 94 to the silicon control switch 107 be inverted, such that a positive pulse is fed to the silicon control switch 107 by the second photocell 94 when the latter is deenergized.

An emitter follower 108 is connected to the junction of the diode 104 and the capacitor 106. The emitter follower 108 serves to read the voltage across the capacitor 106 at any given time with insignificant discharging of the capacitor 106. This signal is in turn fed to a servo mechanism in a manner as will be hereinafter described.

The relay coil 110 operates a pair of single throw switches 111 and 112, and a single pole double throw switch 113 having a normally closed contact 113a and a normally open contact 113b. The switch 111 is placed between the output of the emitter follower 108 and the servo mechanism. The switch 112 is placed in a series circuit with a time delay switch 114 and the normally open contact 11311 of switch 113 and a reset relay coil 115 across the source of electrical power. The time delay switch 114 is arranged such that when switch 112 is closed and switch 113 is closed across contact 11317 electrical current will flow to the reset relay coil 115 after a predetermined time period has passed. The third photocell 98 is connected to the contact 113a such that when switch 113 is closed through contact 113a the third photocell 98, when energized, will energize the reset relay coil 115. Additionally, the contact transducer 42 on the deflector 40 is arranged to energize the reset relay 115 if the deflector is hit by an arrow.

A normally open shorting switch 116 is closed by action of the reset relay 115 and is arranged across the power source from the junction of the constant current generator 100 and the first silicon control switch 102. A second normally open shorting switch 117, also operated by the reset relay 115, is arranged across the capacitor 106. Since the system must operate rapidly, the relays preferably are comprised of reed switches or the like.

As mentioned previously, the output of the emitter follower 108 is fed through the switch 111 when the latter is closed to a servo mechanism. The servo mechanism comprises a magnetic modulator 119 of conventional construction which converts the DC input signal to an alternating current signal. Preferably, on appropriate leads, a DC bias is placed on the magnetic modulator 119 so as to achieve a linear response in the servo mechanism. The output of the magnetic modulator 119 is fed to a gain potentiometer 120 and then to a servo amplifier 121 which may be of conventional construction. The amplifier 121 is then connected to a conventional servo motor 122. Associated with the output of the servo motor 122 is a variable resistor 122a connected across a suitable DC source. The wiper 122b of the resistor 122a is linked by suitable means 1220 to the servo motor 122 and is moved therewith when the motor 122 responds to an input signal. Through appropriate leads the resulting signal from the resistor 122a is fed back to the modulator 119 and is arranged to balance the input signal when the servo motor 122 has fully responded thereto to preclude further movement thereof. The operation of the circuit in conjunction with the target monitor 38 will be described hereinafter.

FIGURES 7, 8 and 9 show the mechanism by which the arrow position is indicated oin the target monitor 38. The target monitor 38 comprises a translucent facing 130 bearing indicia, corresponding to that on the target 26,

mounted in front of the indicating mechanism. The indicating mechanism includes a pair of servo motors 122 and 123, each operated by one system of the scanning mechanism 25. The servo motor 122 mounts an arm 126 which is adapted to rotate across the translucent facing 130 to the position dictated by its scanning circuit. The servo motor 123 is mounted adjacent an opposite corner of the translucent facing 130 and also mounts a similar anm 127. The arm 127 supports an indicating lamp 136 mounted on a movable carriage 132. The carriage 132 includes grooved wheels 134 mounted on tracks 128 on either side of the arm 127. The carriage 132 is springbiased by a constant tension spring 140 toward the upper extremity of the arm 127. Mounted on one side of the carriage 132 and in line with the longitudinal axis of the indicating lamp 136, is a cam follower 138 arranged in the path of the arm 126. As will be noted in FIG. 8, the arms 126 and 127 are slightly oflset from parallel lines, 126a and 127a respectively, intersecting the center of rotation of their respective servo motors. The position of the indicating lamp 136 and the cam follower 138 on the carriage 132 is such that the lamp 136 will be located at the intersection of the parallel line for each arm when the carriage is moved under the influence of the two arms 126 and 127. This construction assures that the lamp 136 will always be positioned at the exact angle of interception of the arrow regardless of its position with respect to the lengths of the two arms 126 and 127.

The operation of the scanning and indicating mechanism is as follows: Again since the respective scanning and indicating mechanisms for each of the two coordinates of the arrow hit upon the target 26 are the same. the operation of only one will be described. Initially, the capacitor 106 has a zero charge. As the beam of light begins its sweep across the flight path, the first photocell is energized which supplies a short pulse to the first silicon control switch 102. This causes the silicon control switch 102 to conduct and to be locked on. The capacitor 106 is then charged linearly by the constant current generator through the diode 104. If during the sweep of the light beam across the flight path, an arrow is present, the second photocell 94 is momentarily deenergized and by virtue of its reversed polarity connection to the second silicon control switch 107, the latter receives a positive pulse, begins to conduct and is also looked on. Accordingly, relay is energized closing switches 111, 112 and moving the switch 113 to the contact 113b. Because of the low impedance of relay 110, the constant current generator 100 is effectively shorted out. This precludes the capacitor 106 from charging further, while the diode 104 precludes the capacitor 106 from discharging through the second silicon control switch 107. With the closing of the switch 111, the voltage on the capacitor 106 is applied through the emitter follower 108, to the magnetic modulator 119 where it is transformed into an alternating current signal, to the amplifier 121, and thence to the servo motor 122 which responds accordingly, moving its arm across the translucent facing 138. Thus, when the servo motors 122 and 123 are actuated by signals from their respective scanning circuits, they respectively move the arms 126 and 127 to positions across the translucent facing 130 corresponding to the angles of interception of the arrow. The camming action of arm 126 on the cam follower 138 of the carriage 132 forces the 0 indicating lamp 136- to one of the appropriate coordinates corresponding to the arrow hit on the target, while the movement of the carriage 132 by arm 127 positions the indicating lamp 136 at the other coordinate of the arrow hit on the target. At this point, the lamp 136 indicates through the translucent facing 130 and the indicia thereon the position at which the arrow hit the target 26. This position will be held until the device is reset by the time delay switch 114 Simultaneously, with the closing of switch 112 and the moving of switch 113 to contact 113b, which takes the third photocell 98 out of the circuit to prevent premature energization of reset relay 115, the time delay switch 114- is energized and after a predetermined time period will energize reset relay coil 115. Upon the energization of reset relay coil 115, shorting switches 116 and 117 are closed. The closing of the shorting switch 116 diverts the current from the two silicon control switches 102 and 107, which then revert to an off status. This action additionally stops the flow of current through relay 110 causing switches 111 and 112 to open and switch 113 to move back to the contact 113a, which takes the servo mechanism and the time delay switch, respectively, out of the circuit. Simultaneously, with the closing of shorting switch 116, shorting switch 117 is closed thereby shorting out the capacitor 106 and reducing the charge thereon to zero. The system is now ready for the next arrow.

If no arrow is present in the flight path, the capacitor 106 is charged as before. In this case, the third photocell 98 will be momentarily energized by the beam of light ending its sweep across the flight path, which will energize relay 115 through the normally closed contact 113a of switch 113, thereby closing shorting switches 116 and 117. Again, the first silicon control switch 102 is turned off and the capacitor 106 has its charge reduced to zero, thus readying the system for the next arow. Additionally, if desired, a manually operated switch 118 can be placed in the circuit to selectively energize the reset relay 115 to reset the system. Should an arrow strike the deflector 40, the control transducer 42 will energize the reset relay 115.

It will be apparent from the foregoing that the capacitor 106 acts as a timer, measuring the time from the beginning of the sweep of the light beam across the flight path to the time at which the beam of light is broken by an arrow in terms of the voltage of its charge. It will be additionally noted that the presence of the time delay switch 114 is required to permit the servo mechanism to respond to the charge across the capacitor 106 and to permit an archer or spectators to visually observe the resulting indication on the target monitor 38.

It will be apparent that a scanning system according to the invention, such as that detailed above, provides great advantages over the sensing systems of the prior art. Because the system does not rely on mechanical or actual physical contact with the arrow passing through the target as do prior art devices, there is no arrow injuring contact and the sensing of the position of the arrow as it passes within the flight path and through the target with means according to the invention is significantly more accurate. This is particularly true where the arrow hits the boundaries between adjacent target areas. Devices of the prior art, in such situations, either indicate that both target areas have been hit by an arrow or rely on a complex system of electronic circuitry which arbitrarily decides that the arrow has hit one area or the other. By way of contrast, when a scanning system according to the invention is used, the point at which the arrow hits the target need only be ascertained visually on the target monitor by the archer and scored in accordance wit-h the established rules governing hits on target area boundaries. Thus, when a conventional method of scoring an archery game is used, the target sensing and indicating means according to the invention provide a significantly greater degree of accuracy in scoring than is obtainable with prior art devices.

Briefly, the overall operation of the range is as follows. The archer 22 steps to the firing line and fires an arrow 24 at the target 26. Just prior to the hitting of the target 26 by the arrow 24, the arrow 24 passes through the scanning mechanism 25 causing the scanning circuitry and servo mechanism to respond in the manner previously described to indicate the point of entry of the arrow into the target 26 to the archer 22 or spectators on the target monitor 38. The arrow 24 hits the target 26, passes partially through the grids 50, is stopped by the plate 52 of the backstop 28, and comes to rest lying loosely within the grids 50 to be observed by the archer.

The score of the shot is recorded and the scanning system is then reset either automatically by the time delay switch 114 or by manual operation of switch 118. Additional arrows 24 may then be fired as desired, causing the above sequence to be repeated. At some point, the backstop 23 will have received its programmed number of arrows 24 and will automatically eject the arrows 24 onto the collectors 29. From the collectors 29, the arrows 24 will be transported without injury thereto by the belts 30a, 30b, 32, 34a, 34b to the firing line 20 and deposited in the quiver 36 to be held in readiness for the archer 22.

Of course, it will be appreciated that the use of an automated range according to the invention takes much of the danger and drudgery out of archery. Additionally, while not being limited thereto, such a range is particularly well suited for the playing of an archery game such as that described hereinafter, as well as for league play because of the time-saving automation thereof and the various features providing ready adaptability to various target arrangements and combinations of the number of arrows to be fired.

While the use of a suitable projector 27 such as that shown in FIGURE 1 for projecting target markings onto the screen facing is not critical, it is extremely desirable as it considerably enhances the flexibility of the range. In this connection, it has been previously noted that such a projector may be programmed with a number of diflerent target markings for differing games, any one of which may be selected at will by the archer. It will be further appreciated that through use of a plurality of slides of differing imag size, or through a suitable focusing arrangement, the size f the image projected on the screen facing may be changed to vary the difiiculty in hitting the target without modifying the length of the range. Such a construction is particularly advantageous where a range is to be used alternatively by experts and beginners. Furthermore, a moving picture projector can be used to project a moving target image. Through suitable electrical connections with the scanning mechanism, the projector can be made to freeze the image on the screen facing when an arrow passes therethrough to enable the archer to determine where he has hit the moving target image.

To facilitate the rapid changing of target indicia by an archer or the use of moving target indicia, a suitable optical system (not shown) in conjunction with the projector 27 or a second projector 39 may be used to project a corresponding image on the target monitor 38.

Having disclosed a specific embodiment of our invention, we do not intend that our invention be limited to the specific construction set forth, but rather construed broadly according to the true spirit thereof as set fort-h in the following claims.

We claim:

1. A sensing apparatus for targets adapted to be hit by missiles within a flight path comprising: first and second systems for respectively determining a first and second coordinate of the missile within the flight path, each of said systems including means for sweeping a beam of energy across the flight path, timing means for timing the sweep of the beam of energy across the flight path, means responsive to the beginning of the sweep of the beam of energy across the flight path for actuating said timing means, means responsive to the presence of a missile in said flight path in said beam of energy for deactuating said timing means; means responsive to the termination of the sweep of said beam of energy across the flight path for resetting said timing means; and means for reading said timing means and adapted to feed the reading to an indicating mechanism.

2. The invention of claim 1 wherein said means for sweeping a beam of energy across the flight path comprises a motor, a drum having a plurality of equally spaced apertures in its periphery associated with said motor to be rotated thereby, and a source of light mounted within said drum whereby when said drum is rotated, light from said source is projected through said apertures in rotating, sweeping beams across the flight path, the axis of rotation of the drum of the first system being spaced from the axis of rotation of the drum of the second system.

3. The invention of claim 1 wherein said beam of energy is a beam of light and said means responsive to the beginning of the sweep of the beam of energy includes a photocell spaced from said means for sweeping a beam of light along one edge of the flight path; said means responsive to a missile present in the light beam includes a reflective element placed along at least part of the periphery of the flight path and a photocell placed in such a relation to said reflective element and said means for sweeping a light beam across the flight path as to receive any beam of light sweeping across said target and reflected by said reflective element; and said means responsive to the termination of the sweep of a beam of light across the flight path includes a photocell spaced from said means for sweeping a beam of light along another edge of the flight path.

4. The invention of claim 1 wherein said beam of energy is a beam of light and said timing means includes a capacitor in a linearly charging circuit; said means responsive to the beginning of the sweep of the energy beam includes photo sensitive switch means for energiz ing said circuit; said means responsive to the presence of a missile in the energy beam includes photo sensitive switch means in said circuit for diverting current from said capacitor; and said means responsive to the termination of the sweep of the energy beam includes photo sensitive switch means for shorting out said capacitor to reduce the charge thereon to zero.

5. A sensing apparatus for detecting the location of missiles within a flight path to determine the location of a missile on two coordinates comprising: first and second systems, each including means for sweeping a beam of energy across the flight path; position identifying means associated with said sweeping means for providing a signal of differing magnitudes, each magnitude being indicative of a unique position of the beam along one coordinate with respect to the flight path; and means responsive to the disruption of said beam by the pres ence of a missile therein for stopping said position identifying means whereby the magnitude of said signal will indicate the position of the beam with respect to the flight path at the time a missile was in the beam and thus the position of the missile along one coordinate within the flight path; the sweeping means of each said systems being spaced from each other about the flight path.

6. A sensing apparatus for targets adapted to be hit by missiles within a flight path comprising: means for sweeping a beam of energy across the flight path; position identifying means associated with said sweeping means for providing a signal having a characteristic that is a measure of the position of the beam with respect to the flight path; means responsive to the termination of the sweeping of the beam across the flight path for resetting said position identifying means; and means responsive to the presence of a missile in the beam for stopping said position identifying means whereby the characteristic of the signal will indicate the position of the beam with respect to the flight path at the time a missile was in the beam and thus the position of the missile within the flight path.

7. A sensing apparatus for detecting the location of missiles within a flight path comprising: means for sweeping a beam of energy across the flight path; position identifying means associated with said sweeping means for providing an identifiable condition that is a measure I of the position of the beam with respect to the flight path; means responsive to the initiation of the sweeping of the beam across the flight path for activating said position identifying means; means responsive to the termination of the sweeping of the beam across the flight path for resetting said position identifying means; and means responsive to the presence of a missile in the beam for stopping said position identifying means whereby the condition thereof will indicate the position of the beam with respect to the flight path at the time a missile was in the beam and thus the position of the missile within the flight path.

8. Archery apparatus comprising: means comprising target markings positioned to be hit by missiles fired in a flight path, and means adjacent said target means for scanning said flight path to determine the point at which a missile hits said target means, said scanning means including first and second systems, each including means for generating a sweeping beam of energy, said first system including means for determining one coordinate of a missile in said flight path, and said second system including means for determining the second coordinate of a missile in said flight path; said determining means each including a position signal generating means, means synchronizing said signal generating means with said beam of energy generating means, and means responsive to the presence of a missile in said beam of energy for stopping said signal generating means.

9. Archery apparatus comprising: means comprising target markings positioned to be hit by arrows fired in a flight path, and means adjacent said target means for scanning said flight path to determine the point at which an arrow hits said target means, said scanning means including first and second systems, each including means for generating a sweeping beam of energy, said first system including means for determining one coordinate of an arrow in said flight path, and said second system including means for determining the second coordinate of an arrow in said flight path; said determining means each including a position signal generating means, means synchronizing said signal generating means with said beam of energy generating means, and means responsive to the presence of a missile in said beam of energy for stopping said signal generating means, each of said systems further comprising: means for moving said beam of energy across the flight path, timing means, means responsive to a beam of energy moving across the flight path for actuating said timing means, means responsive to the presence of an arrow in said flight path for deactuating said timing means and means responsive to a beam of energy moving past the flight path for resetting said timing means.

10. The invention of claim 9 further including means for reading said timing means and adapted to feed the reading to an indicating mechanism.

11. The invention of claim 1 further including an indicating means comprised of a target monitor adapted to be remotely located from a target and a visible indicator on said target monitor actuated by a servo mechanism responsive to said reading means.

12. The apparatus of claim 1 wherein each of said sweeping means is arranged to sweep a beam of energy across the flight path at a predetermined position with respect thereto at a rate sufficiently rapid so that a missile cannot pass through said flight path without having the beam of energy impinge thereon.

13. A sensing apparatus according to claim 6 wherein said position identifying means comprises timing devices and said signal characteristic is proportional to a time factor.

14. A sensing apparatus according to claim 6 wherein said sweeping means comprises a source of energy, means associated with said source of energy for providing a beam of energy, and movable means associated with said source and said beam providing means for moving the beam of energy across the flight path.

15. A sensing apparatus according to claim 6 wherein said means responsive to the presence of a missile in the beam comprises reflective means disposed about the flight path for normally reflecting said beam, means normally receiving said reflected beam and means responsive to the absence of reflection of the beam due to interruption of the beam by a missile for deactuating said position identifying means.

16. The apparatus of claim 6 wherein sweeping means are arranged to sweep a beam of energy across the flight path at a predetermined position with respect thereto at a rate sufiiciently rapid so that a missile cannot pass through said flight path without having the beam of light impinge thereon.

17. A sensing apparatus for determining the position of a missile within a flight path comprising: a pair of systems, each spaced from the other about the flight path, for determining first and second coordinates of a missile within the flight path, each of said systems including:

(a) a source of energy;

(b) means associated with said source for providing a beam of energy;

(c) means associated with said source and said beam providing means for moving the beam of energy across the flight path;

(d) timing means;

(e) means associated with said beam moving means for sensing the initiation of the movement gr the beam across the flight path and for actuating said timing means;

(i) means associated with said beam moving means for sensing the termination of movement of said beam across the flight path and for resetting said timing means; and

(g) means responsive to the interruption of said beam by a missile within the flight path for deactuating said timing means including means located about the flight path for normally reflecting said beam, sensing means for normally receiving the reflected beam and means responsive to said sensing means when a reflected beam is not sensed thereby.

18. The sensing apparatus of claim 17 wherein said deactuating means further includes means responsive to the interruption of said beam by a missile in the flight path for at least temporarily precluding operation of said resetting means so that the condition of said timing means may be determined to provide an indication of the coordinate of the missile within the flight path.

References Cited UNITED STATES PATENTS 2,081,134 5/1937 Buckley 250222 X 2,113,899 4/1938 Oram 273-102.20 X 2,362,473 11/1944 Dunham 250-222 X 2,376,162 5/1945 Merriman et al. 250-222 X 2,419,459 4/ 1947 McDowell et a1. 250-221 2,581,738 1/1952 Williams 250-222 X 3,025,406 3/1962 Stewart et a1. 273--102.2 X 3,047,723 7/ 1962 Knapp 250-222 3,061,727 10/1962 Roth et al. 2731O2.2 X 3,229,975 1/ 1966 Tompkins et a1. 273-26 ANTON O. OECHSLE, Primary Examiner.

M. R. PAGE, Assistant Examiner. 

